This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Manual therapies such as joint mobilization/manipulation have been shown to affect motoneuron pool excitability. The overall aim of this project is to determine the effect of local and distant mobilization/manipulation interventions on pre-synaptic and post-synaptic inhibition of the quadriceps muscle in individuals with existing quadriceps inhibition. This will be a double-blinded randomized controlled trial in which 75 subjects will be randomly assigned to receive one of four manual therapy interventions or no treatment and will be compared on measures of quadriceps muscle activation. Outcomes will be the measurements of peak-to-peak H-reflex, paired reflex depression, and recurrent inhibition over time This study will help elucidate the mechanisms responsible for improved muscle function following manual therapy interventions in people with muscle weakness. The specific effects from performing the treatment near the affected body part or at the lower back/pelvic region will be determined. This information will help develop optimal use of manual therapy treatments in people with muscle weakness secondary to injury.